Implant with bioactive particles stuck and method of manufacturing the same

ABSTRACT

An implant includes a main body member having bio-compatibility, and particles formed of bioactive material and dispersedly provided at the surface of an embedded section of the main body member. Each of the particles has a part embedded in the embedded portion and the other part protruding from the embedded portion. The main body member is formed of titanium or titanium alloy. The particles having osteo-conduction are formed of a material selected from among a group consisting of sintered substances of hydroxylapatite, α-tricalcium phosphate, β-tricalcium phosphate, tetra-calcium phosphate, a single substance of amorphous calcium phosphate, monetite, brushite, 45S4 glass, and a mixture of them. It is desirable that the embedded section surface has a surface roughness in a range of 5 to 50 μm.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to an implant such as an implantembedded in bones and a dentistry implant and a method of manufacturingthe same, and more particularly to an implant with bioactive particlesstuck and a method of manufacturing the same.

[0003] 2. Description of the Related Art

[0004] Titanium or titanium alloy is generally used as material ofimplants such as an implant embedded in bone and a dentistry implant atpresent. This is because when the implant is installed, the material ofthe implants has a state called “osteo-integration” in which the implantdirectly contacts bone. The osteo-integration implies the state in whichthere is no connective tissue between the bone and the implant. If othermaterial is used, there is a case that the osteo-integration is notrealized and a fibrous connective tissue is intervened between theimplant and the bone. For this reason, the whole implant is finallycovered by the fibrous connective tissue so that the fluctuation of theimplant starts. Therefore, the implant must be pulled out.

[0005] In order to further increase the effect of the osteo-integration,it could be considered that the surface of the implant is made rough.There could be various methods of making the implant surface rough. Forinstance, as one of the methods, there is a method in which beads ofmetal titanium are sprayed in plasma such that the surface of theimplant has many hemispheric titanium (Ti) protrusions in a microscopelevel and the surface area of the implant is increased. This techniquealso makes it possible to increase the bio-compatibility of the implantwith bone cells. Another method is a sand blasting method using grindingparticles of alumina and so on. In this method, the surface area of theimplant is increased to reflect the size of the grinding particles.Also, an anchor effect is achieved because bone enters into concaveportions of the implant.

[0006] Also, the implant that a hydroxylapatite (HAP) layer is coated onthe surface of the implant of titanium is commercially available. Insuch an implant, the connection state between the bone and thehydroxylapatite layer is called bio-integration, and it is said that theimplant and the bone are chemically coupled to each other. Thebio-integration is stronger than the osteo-integration in couplingstrength. In a method of-coating the hydroxylapatite layer, a powder ofhydroxylapatite is adhered to the surface of the implant by a plasmathermal spraying method and so on. Because the hydroxylapatite layer ofthe implant is an aggregation of powder, the surface of the implant hasportions with very small unevenness and has the above-mentioned anchoreffect.

[0007] However, there are the following problems in the above-mentionedconventional implants. In the implant having the surface where the beadsof titanium are sprayed in the plasma, because the plasma sprayingmethod is the very advanced technique which requires high cost, thefinal implant cost becomes very expensive. On the other hand, it ispossible to manufacture with low cost the implant having the surfacewhich is subjected to the sand blasting process using the aluminagrinding particles. However, there is a problem in that it is difficultto remove the adherent alumina grinding particles so that bioinertalumina particles are remained on the surface of the implant. Therefore,the formation of osteo-integration is prevented.

[0008] Further, it is in the present situation that there is littleimplant that the hydroxylapatite layer is coated as the commerciallyavailable products. The reason is that advanced technique is needed inthe hydroxylapatite coating and it is costly. Also, the reason is thatthe implant having a titanium surface is finally superior to the implanthaving the hydroxylapatite layer, because bone coupling state isdestructed through delamination of the hydroxylapatite coating layer.

Summary of the Invention

[0009] In view of these points, the inventors of the present applicationperformed various types of study and experiment as for the implantsurface which had suitable roughness to bone and which could realizeosteo-integration. As a result, the inventors found out a method offorming an implant having a stable surface, in which the implant had thegood property of the implant having the titanium surface and the goodproperty of the implant having the HAP coated surface. The implant canbe simply manufactured from bioactive particles having osteo-conductionwith low cost without bioinert impurity such as alumina particles.

[0010] Therefore, an object of the present invention is to provide animplant which has the good property of an implant having a titaniumsurface and the good property of an implant having a hydroxylapatitecoated surface, and a method of manufacturing the same.

[0011] Another object of the present invention is to provide a method ofmanufacturing bioactive blasting particles.

[0012] Still another object of the present invention is to provide animplant having bioactive particles on its surface and a method ofmanufacturing the same.

[0013] In order to achieve an aspect of the present invention, animplant includes a main body member having bio-compatibility, andparticles formed of bioactive material and dispersedly provided at aprocessed surface of at least a portion of the main body member suchthat each of the particles has a part embedded in the processed surfaceand a part protruding from the processed surface.

[0014] It is desirable that the processed surface has a surfaceroughness in a range of 5 to 50 μm, and more desirably, 15 to 30 μm.Also, it is desirable that at least a part of the processed surfaceincludes a surface formed of one of titanium, titanium alloy andtitanium oxide.

[0015] The portion corresponding to the processed surface includes athread portion provided on the entire of the portion. In this case, thethread portion is low in height in a region near an end of the portionand is high in height in a region apart from the end of the portion.Alternatively, the portion corresponding to processed surface mayinclude a thread portion provided in a region apart from an end of theportion.

[0016] Also, the particles have osteo-conduction. For example, theparticles are formed of a material selected from among a groupconsisting of sintered substances of hydroxylapatite, α-tricalciumphosphate, β-tricalcium phosphate, tetra-calcium phosphate, a singlesubstance of amorphous calcium phosphate, monetite, brushite, 45S4glass, and a mixture of them. Each of at least particles of theparticles may have a hydroxylapatite layer at the protruding part.

[0017] In order to achieve another aspect of the present invention, amethod of manufacturing an implant, includes the steps of:

[0018] providing a main body member having biocompatibility; and

[0019] dispersedly providing particles formed of bioactive material at aprocessed surface of at least a portion of the main body member suchthat each of the particles has a part embedded in the processed surfaceand a part protruding from the processed surface.

[0020] At least a part of the processed surface includes a surfaceformed of one of titanium and titanium alloy. Also, the particles haveosteo-conduction. For example, the particles are formed of materialselected from among a group consisting of sintered substances ofhydroxylapatite, α-tricalcium phosphate, β-tricalcium phosphate,tetra-calcium phosphate, a single substance of amorphous calciumphosphate, monetite, brushite, 45S4 glass, and a mixture of them.

[0021] The dispersion of the particles may be achieved by performing aprimary sand blasting process to the processed surface using theparticles. In this case, the primary sand blasting process is performedwhile the main body member is rotated.

[0022] In order to still another aspect of the present invention, amethod of manufacturing an implant, includes the steps of:

[0023] providing a main body member having bio-compatibility;

[0024] making a processed surface of at least a portion of the main bodymember rough; and

[0025] dispersedly providing particles formed of bioactive material atthe processed surface such that each of the particles has a partembedded in the processed surface and a part protruding from theprocessed surface. The processed surface has a surface roughness in arange of 5 to 50 μm.

[0026] In order yet still another aspect of the present invention, amethod of manufacturing an implant, includes the steps of:

[0027] providing a main body member having bio-compatibility;

[0028] dispersedly providing particles formed of bioactive materialincluding calcium phosphate at a processed surface of at least a portionof the main body member formed of titanium or titanium alloy such thateach of the particles has a part embedded in the processed surface and apart protruding from the processed surface; and

[0029] forming a titanium oxide layer on the processed surface and ahydroxylapatite layer on a surface of each of the particles.

[0030] The formation titanium oxide layer may be achieved by performinghydrothermal process to the processed surface at least. In this case, asolution used in the hydrothermal process is selected from among a groupconsisting of pseudo-humor, suspension or saturated solution of calciumphosphate, and mixture solution of them.

[0031] The method may further include the step of performing a secondarysand blasting process to the processed surface using secondary blastingparticles formed of bioactive material such that each of the secondaryblasting particles has a part embedded in the processed surface and apart protruding from the processed surface.

[0032] In this case, the particles are formed from the following steps.That is, the step of forming the particles includes:

[0033] producing amorphous calcium phosphate by a precipitate method byadding phosphoric acid solution to calcium hydroxide suspension;

[0034] sintering the amorphous calcium phosphate at a predeterminedtemperature; and

[0035] crushing the sintered amorphous calcium phosphate to select thesintered hydroxylapatite particles using a mesh.

BRIEF DESCRIPTION OF THE DRAWINGS

[0036]FIG. 1A is a front view of a dentistry implant according to afirst embodiment of the present invention;

[0037]FIG. 1B is a partially expanded vertical cross sectional view ofthe dentistry implant shown in FIG. 1A;

[0038]FIG. 2A is a diagram illustrating an example in which a dentistryimplant according to a second embodiment of the present invention isapplied;

[0039]FIG. 2B is a diagram illustrating an example in which a dentistryimplant according to a third embodiment of the present invention isapplied;

[0040]FIG. 3 is a diagram illustrating an example in which an implantaccording to a fourth embodiment of the present invention is applied tofemur.

[0041]FIG. 4 is a diagram illustrating an electron microscope photographof the surface of an implant after a sand blasting process is performed;

[0042]FIG. 5 is a diagram illustrating an electron microscope photographof sand blasting particles which have osteo-conduction and which areused for the sand blasting process;

[0043]FIG. 6 is a diagram of an electron microscope photographillustrating the state in which a sand blasting particles is stuck intoa main body member as an original implant;

[0044]FIG. 7 is a diagram illustrating an electron microscope photographof the surface of an implant after a sand blasting process is performed;

[0045]FIG. 8 is a diagram illustrating a measuring result of a portionshown in FIG. 7 by an EPMA;

[0046]FIG. 9 is a chart obtained as a measuring result of the originalimplant by an X-ray diffractometer after a sand blasting process isperformed using bioactive β-tricalcium phosphate (TCP) particles havinga main peak at about 2θ=31.0°;

[0047]FIG. 10 is a chart obtained as a measuring result of the originalimplant by the X-ray diffractometer after the original implant used forthe measurement shown in FIG. 9 is rinsed with 2N hydrochloric acid forone minute;

[0048]FIG. 11 is a flow chart to explain a method of manufacturing animplant of the present invention;

[0049]FIG. 12 is a schematic front view of a blade-type implant when themanufacturing method is applied to the blade-type implant;

[0050]FIG. 13 is a schematic front view of a dentistry implant when themanufacturing method is applied to the dentistry implant; and

[0051]FIG. 14 is a cross sectional view of an implant to which themanufacturing method is applied.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0052] The implant of the present invention will be described below indetail with reference to the accompanying drawings.

[0053]FIG. 1A shows the structure of a dentistry implant according tothe first embodiment of the present invention. Referring to FIG. 1A, adentistry implant 1 is formed of material having bio-compatibility suchas titanium or titanium alloy. The dentistry implant 1 is composed of anembedded section 3 embedded in jawbone 2, a gingiva penetrating section5 to be located in gingiva, and a crowned section 6 which is located onthe gingiva penetrating section 5. A thread is formed on the surface ofthe embedded section 3. As shown in FIG. 1B, the thread of an upperportion corresponding to a cortical bone section has a triangular crosssection and the thread of a lower portion corresponding to a bone marrowsection has a trapezoidal cross section. Therefore, the thread of theupper portion is higher than the thread of the lower portion by apredetermined height, e.g., 0.1 mm. This height difference makesinsertion of the implant easy. In this example, the heights of thethread portions are different in a step manner. However, the height ofthe thread may change in a continuous manner. That is, the height of thethread may be smallest in the lowermost portion and may become graduallylarger toward the uppermost.

[0054]FIG. 2A shows the structure of a dentistry implant 1′ according tothe second embodiment of the present invention. Referring to FIG. 2A, adentistry implant 1′ is formed of bio-compatible material such astitanium or titanium alloy, as in the first embodiment. The implant 1′is composed of an embedded section 3 embedded in jawbone 2, and agingiva penetrating section 5 to be located in gingiva 23. There is nocrowned section 6. A thread is formed on the whole surface of embeddedsection 3. A concave portion is formed inside of the gingiva penetratingsection 5 such that an abutment 21 can be fit into the concave portionto form a crowned section 6.

[0055]FIG. 2B shows the structure of a dentistry implant 1″ according tothe third embodiment of the present invention. Referring to FIG. 2B, adentistry implant is formed of bio-compatible material such as titaniumor titanium alloy, as in the first embodiment. Unlike the implant shownin FIG. 2A, in the implant in the third embodiment, a thread is formedon only the upper portion of the embedded section 3 corresponding to thecortical bone section. A concave portion is formed inside of the gingivapenetrating section 5 such that an abutment 21 can be fit into theconcave portion as a crowned section 6.

[0056]FIG. 3 shows a use example of an implant 1′″ according to thefourth embodiment of the present invention. In this embodiment, theimplant 1′″ is embedded in femur sections to couple femur sections.

[0057] In the implants shown in FIGS. 1A, 2A and 2B, the whole surfaceof the embedded section 3 of the implant main body member as an originalimplant is made rough and bioactive particles having osteo-conductionare stuck on the whole surface of the embedded section 3. However, therough surface portion with stuck particles may be formed only below theupper portion of the thread portion.

[0058] Referring to FIG. 11, a method of manufacturing of the implant 1in the first embodiment will be described below.

[0059] In a step S2, the gingiva penetrating section 5 and the crownedsection 6 of the main body member of titanium as an original implant 1are masked not to be hit with grinding particles. Then, while theoriginal implant is rotated, a primary sand blasting process isperformed to the surface of the embedded section 3 of the originalimplant 1 using the grinding particles as the first sand blastingparticles having an average grain diameter of 0.2 mm such as aluminaceramic particles, silica particles, and glass bead particles. As aresult, the surface of the embedded section 3 of the original implant 1is made rough. In this case, the roughness of the surface of theembedded section 3 is desirably in a range of 5 to 50 μm, and moredesirably 15 to 50 μm, which fits to the size of osteocyte. After that,ultrasonic cleaning is performed such that the grinding particles suchas alumina ceramic particles, silica particles, and glass bead particlescan be physically removed as much as possible. The primary sand blastingprocess is very effective when the original implant 1 is formed of hardmaterial such as titanium-nickel alloy.

[0060] Next, in a step S4, bioactive sand blasting particles areprepared before a secondary sand blasting process is performed.

[0061] When sintered hydroxylapatite particles are used as the secondsand blasting particles, the sintered hydroxylapatite particles areformed in the following manner. This method is called a precipitatemethod. Amorphous calcium phosphate is synthesized by adding phosphoricacid solution to calcium hydroxide suspension so as to be stoichiometricto hydroxylapatite. The amorphous calcium phosphate is dehydrated,filtered and dried up at the temperature of about 120° C. After that, itis crushed by a crushing machine, and then is calcined at thetemperature of about 800° C. for 1 hour. At this time, the rates oftemperature increase and decrease are set to about 100° C./Hr. Next,polyvinyl alcohol aqueous solution of about 3 wt % is added to thepowder which is obtained by this calcination so as to be equivalent.Further, triethylene glycol of about 1 wt % is added. Then, it is wellmixed and kneaded by an automatic mortar. The mixture is dried up at thetemperature of about 600° C. together with the mortar, and thenfine-ground to form powder. Then, the fine-ground powder is classifiedusing a sieve of the #200 mesh, and the classified powder under thesieve is used as granulation powder. The granulation powder obtained inthis way is subjected to 1-axis formation at about 60 to 80 MPa to forma cake, and it is sintered at the temperature of about 1100° C. Finally,the sintered cake is ground and classified using #80 to 200 meshes.Thus, the sintered hydroxylapatite particles or pieces having the grainsize of about 50 to 200 μm are obtained as the sand blasting particles.

[0062] Alternatively, the amorphous calcium phosphate is dehydrated,filtered and dried up at the temperature of about 120° C. After that,the amorphous calcium phosphate is sintered at the temperature of about1250° C. Finally, the sintered amorphous calcium phosphate is crushedand classified using #16 to 280 meshes. Thus, the sinteredhydroxylapatite particles having the grain size of about 50 μm to 1 mmare obtained as the sand blasting particles. The sand blasting particlesor pieces thus obtained are shown in an electron microscope photographof FIG. 4.

[0063] The method of forming sintered tricalcium phosphate particles issubstantially the same as the method of forming sintered hydroxylapatite(HAP) particles. However, in the step of synthesizing amorphous calciumphosphate, phosphoric acid solution is added to be stoichiometric totricalcium phosphate. Also, if the crystal structure of target particlesis β tricalcium phosphate, the calcination temperature is set in a rangeof about 730 to 780° C. and the sintering temperature is set in a rangeof about 950 to 1130° C., for example. Preferably, the calcinationtemperature is set to about 750° C. and the sintering temperature is setto about 1000° C., for example. On the other hand, if the crystalstructure of target particles is a tricalcium phosphate, the calcinationtemperature is set in a range of about 1100 to 1200° C. and thesintering temperature is set in a range of about 1200 to 1280° C.Preferably, the calcination temperature is set to about 1150° C. and thesintering temperature is set to about 1250° C. Finally, a sintered cakeis ground and classified using #80 to 200 meshes. Thus, the sinteredtricalcium phosphate particles or pieces having the grain size of about50 to 200 μm are obtained as the sand blasting particles.

[0064] Next, in a step S6, the secondary sand blasting process isperformed while the original implant 1 which is subjected to the primarysand blasting process is rotated. The secondary sand blasting process isperformed using calcium phosphate ceramic particles which are smallerthan the grinding particles such as alumina ceramic particles, forexample, using α tricalcium phosphate ceramic particles having anaverage grain diameter of 0.05 to 0.2 mm. As a result, the grindingparticles such as the alumina ceramic particles are removed from thesurface of the original implant 1. In this case, the original implant isobtained to have the titanium surface of a surface roughness which isdetermined based on the primary sand blasting process and to have α-tricalcium phosphate ceramic particles remained on the titanium surface.

[0065]FIG. 5 shows an electron microscope photograph of the originalimplant 1 after the secondary sand blasting process is performed usingtricalcium phosphate ceramic particles. It could be seen that the roughsurface is formed on a part of the embedded section 3 of the originalimplant 1.

[0066]FIG. 6 shows an electron microscope photograph of a part of theoriginal implant 1 after the secondary sand blasting process isperformed using the sintered tricalcium phosphate ceramic particles. Itis shown in the center portion that the sintered tricalcium phosphateceramic particle is tightly coupled to the embedded section 3 of thetitanium original implant 1. That is, a tip portion of the sinteredtricalcium phosphate ceramic particle is stuck into the embedded section3 and the other portion is exposed from the embedded section 3.

[0067]FIG. 7 shows an electron microscope photograph of a part of theoriginal implant 1 after the secondary sand blasting process isperformed using the sintered tricalcium phosphate ceramic particles.FIG. 8 shows the measuring result of the part of the original implant 1by an electron probe microanalyzer (EPMA). In FIG. 8, white dotsindicate the presence of calcium. Since calcium is detected from anupper left position, there is a portion of a thread section wherecalcium is not detected. However, it could be seen from FIG. 8 thatcalcium, i.e., hydroxylapatite or calcium phosphate exists on the entiresurface of the embedded section 3 of the original implant 1.

[0068]FIG. 9 shows the measuring result of the original implant 1 by anX-ray diffractometer. The original implant 1 is subjected to thesecondary sand blasting process using sintered β tricalcium phosphateceramic particles. As seen from FIG. 9, the peaks of β tricalciumphosphate appear together with peak of titanium. The calcium phosphatehas the main peak at about 2θ=31 degrees. The measuring result by theX-ray diffractometer after the original implant 1 is rinsed with 2Nhydrochloric acid for one minute is shown in FIG. 10. As seen from FIG.10, the sintered β tricalcium phosphate ceramic particles dissolve andare lost.

[0069] When being blasted toward the original implant 1 to reach thesurface of the original implant 1, the secondary sand blasting particlessuch as the sintered hydroxylapatite (HAP) ceramic particles is brokenand stick into the surface of the original implant 1. As a result, apart of the broken particle is embedded into the original implant 1 andanother portion protrudes from the surface of the original implant 1.These sticking fine particles are not removed by usual ultrasoniccleaning and remained on the surface. If these remained fine particlesare alumina, they are recognized as bioinert material in the living bodyso that osteo-integration is obstructed. However, when these fineparticles are hydroxylapatite (HAP) or tricalcium phosphate having highbio-activity and are formed of the material which is absorbed by bone asin the present invention, these particles have osteo-conduction tocontribute the formation of bone immediately after the implantation ofthe complete implant and to function to help the osteo-integration.

[0070] Also, it is desirable that when the primary sand blasting processis performed for about 30 seconds to 1 minute, the secondary sandblasting process is performed about twice of the primary sand blastingprocessing time, i.e., about 1 to 2 minutes. For this reason, thebioinert grinding particles such as alumina particles can be completelyremoved, although depending on conditions of the sand blastingprocesses.

[0071] The material of the particles used in the secondary sand blastingprocess is desirably sintered substances of hydroxylapatite,α-tricalcium phosphate, β-tricalcium phosphate, tetra-calcium phosphateor the like, a single substance of amorphous calcium phosphate,monetite, brushite, 45S4 glass, other bioactive glass or the like, orthese mixtures.

[0072] Because sintered calcium phosphate ceramic particles are softcompared with a grit of alumina or glass which are used in usual sandblasting processes to metal, it is desirable that the blasting pressureis set to a slightly higher value than the usual sand blasting processeswhen the sintered calcium phosphate ceramic particles or the like areused.

[0073] Considering the remaining effect of the secondary sand blastingprocess particles such as calcium phosphate ceramics and so on, thematerial of the particles is desirably α-tricalcium phosphate,β-tricalcium phosphate, or bioactive glass such as 45S5 glass which haveosteo-conduction and are completely absorbed in a living body. However,because it is relatively difficult to form hard particles from a singlephase of them, it could be considered that the primary sand blastingprocess is performed, eutictic particles with hydroxylapatite areformed, or mixture particles with hydroxylapatite are formed.

[0074] It should be noted that the above alumina ceramic particles andα-tricalcium phosphate ceramic particles can be chosen in size to havevarious diameters, for example, of about 0.1 to 0.5 mm in case of theprimary sand blasting process, and about 0.01 to 0.1 mm in case of thesecondary sand blasting process.

[0075] Referring to FIG. 11, in a next step S8, hydrothermal processingis performed to the original implant 1 which is subjected to thesecondary sand blasting process. The hydrothermal processing isperformed in α-tricalcium phosphate suspension in the temperature of130° C. for 60 hours such that the titanium surface of the originalimplant 1 is converted into a titanium oxide surface. On the other hand,in the portion where the secondary α-tricalcium phosphate ceramicparticles remain, the surfaces of the particles are converted intohydroxylapatite layers. In this manner, a dentistry implant is obtainedin which metal allergy is extremely suppressed and which has the surfaceof a high bio-compatibility. It should be noted that the temperature andtime of the above hydrothermal processing can be selected suitably inaccordance with the condition.

[0076] Various kinds of pseudo-humor such as Hank's balanced saltsolution, various kinds of suspension or saturated solution of calciumphosphate, and mixture solution of them can be used for the hydrothermalprocessing. Different titanium oxide layers are formed on the surface ofthe original implant depending upon the processing temperature, theprocessing time and the kind of solution. However, it is preferable thatthe processing temperature is in a range of about 60 to 200° C. and theprocessing time is in a range of about 24 Hr to 48 Hr. The calciumphosphate ceramic particles and so on which have been remained on thesurface of the original implant in the blasting process are convertedinto the hydroxylapatite in the whole particles or the surfaces underthese process conditions. As a result, they become stable calciumphosphate ceramics.

[0077] Referring to FIG. 11 again, in a next step S10, the thirdly sandblasting process is performed with a low blasting pressure in a range ofabout 0.2 to 0.3 Pa. As a result, on the surface of the original implantwhich is subjected to the secondary sand blasting process or thehydrothermal processing in addition to it, the thirdly sand blastingparticles formed of, for example, α-tricalcium phosphate, β-tricalciumphosphate, and bioactive glass and so on which have highosteo-conduction.

[0078] Next, specific examples 1 to 3 of the present invention will bedescribed. However, the present invention is not limited to theseexamples.

EXAMPLE 1

[0079] Only the secondary sand blasting process is performed to theembedded section 3 of the blade-shaped original implant 1 of titaniumwith the blasting pressure of 0.7 Pa using 45S5 glass particles with anaverage grain diameter of 0.1 mm. By this, as shown in FIG. 12, theblade-shaped implant formed of titanium is obtained to have an initialosteo-conduction, to have suitable surface roughness for bone, andcontain a little amount of 45S5 glass 7. In this case, the gingivapenetrating section 5 and the crowned section 6 are masked such that theblasting particles do not hit. However, the secondary sand blastingprocess may be performed to the gingiva penetrating section 5 and thecrowned section 6. In this example, the original implant is not rotated.However, it may be rotated during the sand blasting process as describedabove.

EXAMPLE 2

[0080] A titanium implant original implant 1 of a cylindrical shape withthe diameter of 4 mm is rotated with the rotation speed of 100 rpm. Theprimary sand blasting process is performed to the embedded section 3with the blasting pressure of 0.4 Pa using alumina ceramic particleswith an average grain diameter of 0.2 mm. In this case, the gingivapenetrating section 5 and the crowned section 6 is masked such that thealumina ceramic blasting particles do not hit the sections. Afterultrasonic cleaning and drying, the secondary sand blasting process isperformed with the blasting pressure of 0.7 Pa using the mixtureparticles in which 45S5 glass particles, β-tricalcium phosphate ceramicparticles and sintered hydroxylapatite ceramic particles are mixed withthe ratio of 1:1:1 and which have the average grain diameter of 0.05 mm.Thus, as shown in FIG. 13, the final implant formed of titanium isobtained which has the surface 8 of a suitable surface roughness tobone. The final implant has an osteo-conduction, and contains bioactiveglass particles and calcium phosphate ceramic particles 9 remained onthe surface and finally completely absorbed into the living body.

EXAMPLE 3

[0081] The primary sand blasting process is performed to the embeddedsection of a blade implant formed of alloy of titanium and nickel withthe blasting pressure of 0.4 Pa, using alumina ceramic particles withthe average grain diameter of 0.2 mm. In this case, the gingivapenetrating section 5 and the crowned section 6 are masked such that theblasting particles do not hit the masked sections.

[0082] After ultrasonic cleaning and drying, the secondary sand blastingprocess is performed with the blasting pressure of 0.7 Pa usingα-tricalcium phosphate ceramic particles 10 having the average graindiameter of 0.05 mm. After that, a hydrothermal process is performed inα-tricalcium phosphate suspension at the temperature of 130° C. As aresult, a titanium oxide film 11 is formed on the titanium surface, andhydroxylapatite layers 12 is formed on the remaining tricalciumphosphate particle surfaces. In this case, some of the tricalciumphosphate particles are converted into hydroxylapatite particles.

[0083] Further, the thirdly sand blasting process is performed with theblasting pressure of 0.3 Pa using α-tricalcium phosphate ceramicparticles. As a result, as shown in FIG. 14, the blade implant formed oftitanium-nickel alloy is obtained which has a suitable surface roughnessto bone. Also, the blade implant has a stable titanium oxide layerformed on the titanium surface, and contains hydroxylapatite of a highbio-compatibility. As a result, α-tricalcium phosphate having anosteo-conduction remains on the surface.

[0084] In the present invention, it should be noted that the “bioactive”material implies material to which the living body does not indicaterejection symptoms, which can chemically couple to bone bybio-integration, and which has bio-conduction which is capability ofattracting osteoblasts and promoting formation of new bone. Theparticles used in the present invention hasve “bio-activity” to realizebio-integration. Therefore, the bioactive particles does not preventosteo-integration between the implant of titanium and bone but helpsrealization of the osteo-integration.

[0085] Also, in the above embodiments and examples, only the dentistryimplant is described. However, the present invention is not limited tothem. The present invention can be applied to an implant coupling boneseach other, as shown in FIG. 3. In this case, at least one of the sandblasting processes is applied to at least a part of the implant.Specifically, it is desirable for the present invention to be applied tothe whole implant.

[0086] Further, in the above embodiments and examples, the whole oforiginal implant is formed of titanium or titanium alloy. However, theoriginal implant may be formed of stainless and platinum and only a partof the original implant corresponding to the embedded section may beformed titanium, titanium alloy or titanium oxide in surface or whole.Alternatively, the original implant may be formed to have a calciumphosphate ceramic coating layer in part or whole.

[0087] In addition, in the above example, the implant has the crownedsection. However, the implant may not have the crowned section as shownin FIGS. 2A and 2B. In this case, an abutment is attached when theimplant is inserted.

[0088] In the present invention, an implant formed of titanium ortitanium alloy is subjected to sand blasting process(es) using particlesformed of sintered hydroxylapatite, sintered tricalcium phosphate, orbioactive glass or the mixture of them. The above materials other thanthe sintered hydroxylapatite are the material absorbed in the bone orsubstituted by the bone.

[0089] These particles stuck into the implant surface through theblasting process prompts formation of new bone around the implantimmediately after the implant is embedded in the bone. The material ofthe particles is gradually absorbed during the formation of new bone,then is completely substituted by the new bone, and finally, theosteo-integration is realized. Thus, the implant is fixed to the bone inthe early step after it is embedded in the bone. Also, after theabsorption of the material, the implant is provided which is coupled tothe bone with stable osteo-integration.

[0090] Also, after the primary blasting process is performed to thesurface of the original implant formed of titanium or titanium alloyusing the particles formed of hard material such as alumina ceramics andsilica. As a result, the implant surface has a predetermined surfaceroughness. The secondary blasting process is performed once again usingthe blasting particles formed of bioactive glass, or sinteredhydroxylapatite, sintered tricalcium phosphate or a mixture of them. Intitanium or titanium alloy, i.e., alloy of titanium and material such asnickel, aluminum, vanadium, it is difficult to form a rough surface oftitanium or titanium alloy with only the blasting particles of calciumphosphate ceramics and so on. However, by employing the primary sandblasting process, it become possible to efficiently form the roughsurface on titanium or titanium alloy surface. In the case of thesecondary sand blasting process with the blasting particles of calciumphosphate ceramics and so on, the secondary sand blasting process isperformed for a longer time than in the primary sand blasting process,if the particles used in the secondary sand blasting process are smallerthan grinding particles used in the primary sand blasting process. As aresult, the grinding particles of alumina ceramics and so on can beremoved.

[0091] Also, the titanium or titanium alloy surface having a roughsurface by calcium phosphate ceramics, bioactive glass and so on issubjected to the hydrothermal process at the temperature of about 60 to200° C. in various types of pseudo-humor and tricalcium phosphatesaturation solution or these mixture solution. As a result, a stablelayer of the titanium oxide film is provided for the blasted titaniumsurface. At the same time, a hydroxylapatite layer is formed on theremaining calcium phosphate ceramic blasting particle surface. By this,the thin stable layer mainly formed of titanium oxide on the titanium ortitanium alloy surface has a function to promote osteo-integration. Atthe same time, the surface of the calcium phosphate ceramic particlesremained in the titanium or titanium alloy surface becomes a stablehydroxylapatite layer. In this manner, the implant is provided whichjoins to bone in the earlier step.

[0092] Further, the thirdly sand blasting process may be performed tothe implant surface, using the particles formed of bioactive glass,sintered hydroxylapatite and tricalcium phosphate, or mixture of them.As a result, the whole surface or bulk is made to have a rough surface.Also, the bioactive particles are stuck into the oxide film layer toallow enough bone formation to be promoted. Such an implant is provided.

[0093] As described above, according to the present invention, a portionof titanium or titanium alloy of the implant which contacts bone issubjected to the sand blasting process with particles such as bioactiveglass. Instead, the portion of titanium or titanium alloy is subjectedto the primary sand blasting process with the hard particles of aluminaceramics and so on and the secondary sand blasting process with theparticles of calcium phosphate ceramics and so on. Or, the portion oftitanium or titanium alloy is subjected to a hydrothermal process suchthat the titanium surface is converted into titanium oxide and a calciumphosphate ceramics part is converted into hydroxylapatite. Instead, thesand blasting process is further performed to the titanium oxide surfaceusing secondary blasting material. In this manner, the implant can beobtained to have the titanium surface which contains the particles whichcontribute to form bone and have a high bio-compatibility. Also, by thismethod, it is made possible to provide a stable and safe titanium ortitanium alloy implant with a low price.

What is claimed is:
 1. An implant comprising: a l main body memberhaving bio-compatibility; and particles formed of bioactive material anddispersedly provided at a surface of a processed portion of said mainbody member such that each of said particles has a part embedded in saidprocessed portion surface and a part protruding from said processedportion surface.
 2. An implant according to claim 1, wherein saidprocessed portion surface has a surface roughness in a range of 5 to 50μm.
 3. An implant according to claim 1, wherein at least a part of saidprocessed portion surface is formed of one of titanium, titanium alloyand titanium oxide.
 4. An implant according to claim 1, wherein saidprocessed portion includes a thread portion provided on an entire ofsaid processed portion.
 5. An implant according to claim 4, wherein saidthread portion is low in height in a region near an end of said mainbody member and is high in height in a region apart from the end of saidmain body member.
 6. An implant according to claim 1, wherein saidprocessed portion includes a thread portion provided in a region apartfrom an end of said main body member.
 7. An implant according to claim1, wherein said particles are formed of a material selected from among agroup consisting of sintered substances of hydroxylapatite, α-tricalciumphosphate, β-tricalcium phosphate, tetra-calcium phosphate, a singlesubstance of amorphous calcium phosphate, monetite, brushite, 45S4glass, and a mixture of them.
 8. An implant according to claim 1,wherein each of ones of said particles has a hydroxylapatite layer atsaid protruding part.
 9. A method of manufacturing an implant,comprising the steps of: providing a main body member havingbio-compatibility; and dispersedly providing particles formed ofbioactive material at a surface of a processed portion of said main bodymember such that each of said particles has a part embedded in saidprocessed surface and a part protruding from said processed surface. 10.A method according to claim 9, wherein at least a part of said processedsurface is formed of one of titanium and titanium alloy.
 11. A methodaccording to claim 9, wherein said particles have osteo-conduction. 12.A method according to claim 9, wherein said particles are formed ofmaterial selected from among a group consisting of sintered substancesof hydroxylapatite, α-tricalcium phosphate, β-tricalcium phosphate,tetra-calcium phosphate, a single substance of amorphous calciumphosphate, monetite, brushite, 45S4 glass, and a mixture of them.
 13. Amethod according to claim 9, wherein said step of dispersedly providingparticles includes performing a primary sand blasting process to saidprocessed portion surface using said particles.
 14. A method accordingto claim 13, wherein said step of performing a primary sand blastingprocess includes performing said primary sand blasting process whilerotating said main body member.
 15. A method according to claim 13,further comprising the step of making said processed portion surfacerough through said step of dispersedly providing particles.
 16. A methodof manufacturing an implant, comprising the steps of: providing a mainbody member having bio-compatibility; making a surface of a processedportion of said main body member rough; and dispersedly providingparticles formed of bioactive material at said processed portion surfacesuch that each of said particles has a part embedded in said processedportion surface and a part protruding from said processed portionsurface.
 17. A method according to claim 16, wherein said processedportion surface has a surface roughness in a range of 5 to 50 μm.
 18. Amethod according to claim 16, wherein said step of making said processedportion surface rough includes performing a grinding particles blastingprocess to said processed portion surface using grinding particles. 19.A method according to claim 16, wherein at least a part of saidprocessed portion surface is formed of one of titanium and titaniumalloy.
 20. A method according to claim 16, wherein said particles areformed of material selected from among a group consisting of sinteredsubstances of hydroxylapatite, α-tricalcium phosphate, β-tricalciumphosphate, tetra-calcium phosphate, a single substance of amorphouscalcium phosphate, monetite, brushite, 45S4 glass, and a mixture ofthem.
 21. A method of manufacturing an implant, comprising the steps of:providing a main body member having bio-compatibility; dispersedlyproviding particles formed of material including calcium phosphate at asurface of a proccessed portion of said main body member formed oftitanium or titanium alloy such that each of said particles has a partembedded in said processed portion surface and a part protruding fromsaid processed portion surface; and forming a titanium oxide layer onsaid processed portion surface and a hydroxylapatite layer on a surfaceof each of said particles.
 22. A method according to claim 21, whereinsaid step of forming a titanium oxide layer includes performinghydrothermal process to said processed portion surface.
 23. A methodaccording to claim 22, wherein a solution used in said hydrothermalprocess is selected from among a group consisting of pseudo-humor,suspension or saturated solution of calcium phosphate, and mixturesolution of them.
 24. A method according to claim 21, wherein saidparticles are formed of material selected from among a group consistingof sintered substances of hydroxylapatite, α-tricalcium phosphate,β-tricalcium phosphate, tetra-calcium phosphate, a single substance ofamorphous calcium phosphate, monetite, brushite, 45S4 glass, and amixture of them.
 25. A method according to claims 21, further comprisingthe step of performing a secondary sand blasting process to saidprocessed portion surface using secondary blasting particles formed ofbioactive material such that each of said secondary blasting particleshas a part embedded in said processed portion surface and a partprotruding from said processed portion surface.
 26. A method accordingto claim 25, wherein said secondary blasting particles haveosteo-conduction.
 27. A method according to claim 26, wherein saidsecondary blasting particles are formed of material selected from amonga group consisting of sintered substances of hydroxylapatite,α-tricalcium phosphate, β-tricalcium phosphate, tetra-calcium phosphate,a single substance of amorphous calcium phosphate, monetite, brushite,45S4 glass, and a mixture of them.
 28. A method according to claim 20,further comprising the step of forming said particles, and wherein saidstep of forming said particles includes: producing amorphous calciumphosphate by a precipitate method by adding phosphoric acid solution tocalcium hydroxide suspension; sintering said amorphous calcium phosphateat a predetermined temperature; and crushing said sintered amorphouscalcium phosphate to select said sintered hydroxylapatite particlesusing a mesh.